1. Field of the Invention
The present invention relates to a device for recycling a recording medium by removing a film-like image forming substance from the medium.
2. Discussion of the Background
In modern offices, various kinds of papers, including printer papers and copier papers, are used in a considerable amount, and most of them are simply discarded. This not only requires extra costs for disposal, but also deteriorates the regional environment due to the disposal. Moreover, excessive lumbering for the production of papers brings about global environmental disruption.
In light of this, it has been customary to recycle used papers by removing ink from the papers, immersing the papers in a liquid, and again making papers. A recent achievement in this respect is a paper which allows character images formed thereon to be removed by cleaning. This kind of paper can be recycled for a copying or printing purpose. Japanese Patent Laid-Open Publication No. 4-67043, for example, discloses a paper having a sheet-like image support whose sides, particularly one side, is treated to have a parting ability. The paper with a parting ability is marked to be distinguished from ordinary papers. However, this paper is a special paper and cannot be easily applied to a copier because of its poor image fixing ability. Japanese Patent Laid-Open Publication Nos. 1-101576 and 1-101577 each teach a method of removing a film-like image forming substance (toner) from an image support by effecting ultrasonic treatment in an organic solvent to which the substance is soluble. However, this kind of scheme is not feasible for ordinary offices and homes because organic solvents are apt to pollute the environment and are inflammable and toxic. Further, Japanese Patent Laid-Open Publication No. 1-297294 proposes a cleaning method practicable with an image support made of plastic, metal, paper having low infiltration, or ceramic. An image formed on such a support is heated with the intermediary of a meltable separating body and removed from the support thereby. However, this method is not practicable without a special paper having surfaces treated for parting.
On the other hand, Japanese Patent Laid-Open Publication No. 4-255916, equivalent U.S. Pat. No. 5,474,617, for example, teaches a device for removing a film-like image forming substance from a recording medium having a swelling layer, which swells with a water-containing image removal promoting liquid, at least in the vicinity of a surface where an image is to be formed. The device has applying means for applying the liquid to the recording medium on which an image is formed by the image forming substance, to thereby cause the swelling layer to swell more than the image forming substance. Separating means separates the substance from the medium by pressing its separating member against the medium to which the liquid has been applied, while heating the medium. As a result, the substance is transferred from the medium to the separating member. It has been reported that this kind of device is capable of removing only the substance from the medium without noticeably damaging the medium or paper. It has also been reported that the separation characteristic, particularly separation ratio available in the event of repeated use, is noticeably dependent on the material of the separating member or the conditions surrounding the device. It is to be noted that the separation ratio refers to the ratio of the area of the substance separated from the medium to the total area of the image; the ratio is 100% when the entire substance is separated or 0% when the substance is not separated at all. The above occurrence results from, among others, the fact that the surface of the separating member contacting the medium deteriorates at a rate which is greatly dependent on the material of the separating member.